The electromagnetic scattering from an aircraft engine inlet, which has a near-resonant property due to the multiple wave bouncing inside the inlet is analyzed by introducing an approximate inverse of the block banded coefficient matrix as a preconditioner. This block bonded preconditioning (BBP) reduces the number of iterations much more than the block diagonal preconditioning (BDP). BBP can be calculated in O(N) operation using matrix partitioning method. The computing time per iteration is O(N 2) in conjugate-gradient type solvers, and O(N log N) in multilevel fast multipole algorithm (MLFMA).

The electromagnetic scattering from an aircraft engine inlet, which has a near-resonant property due to the multiple wave bouncing inside the inlet is analyzed by introducing an approximate inverse of the block banded coefficient matrix as a preconditioner. This block bonded preconditioning (BBP) reduces the number of iterations much more than the block diagonal preconditioning (BDP). BBP can be calculated in O(N) operation using matrix partitioning method. The computing time per iteration is O(N 2) in conjugate-gradient type solvers, and O(N log N) in multilevel fast multipole algorithm (MLFMA).